Investigating the effects of noise exposure on intensification of diabetes mellitus, serum glucose, cortisol level and body weight of the male mice

Noise is considered as one of the harmful factors at industrial environments. It affects human health in different aspects including harmful influences on auditory, vision, neurological and psychiatric systems, hormones, physiological and mental systems. Paying attention to the importance of hormonal effects on human body seems to possess crucial importance. The aim of the present study is to investigate the effects of noise exposure on variation of serum levels of glucose and cortisol at Syrian adult male mouse. 36 Syrian male adult mice were randomly categorized into two experiment and control groups. Garlic powder was added to the mice pelleted food meal (equal to 1% of their daily diet) to study its effect on the cortisol and glucose serum levels. The mice pelleted food contains starch, glucose, isolated soya protein, etc., which are the rich resources of A, C, B1, B2 and B6 vitamins. Streptozotocin (60mg/kg) was injected to the mice at experiment group which were under noise exposure with intensity of 90dB in frequency range of 700-5700Hz. Noise were generated using CoolEdit software and distributed to the fabricated box for 30 days (8h/d).  Fasting cortisol and glucose serum levels were measured for mice of both groups 24h after finishing the exposure period. Results indicated that the glucose serum level in non-diabetic and diabetic subjects under noise exposure had significant difference (p<0.002) with the subjects at control group. Also, cortisol level in non-diabetic and diabetic subjects under noise exposure indicated significant difference (p<0.002) with the subjects at control group. Exposure to noise with intensity of 90dB at frequency range of 700-5700Hz increases the glucose and cortisol serum levels

Investigation of heat stress and heat strain in outdoor workers: a case study in Iran

Heat stress is an important and serious threat at work and is a particular concern in outdoor occupational environments. This study aims at comparing heat stress and heat strain at different outdoor groups, examining the protective and adaptive actions which were done by workers and also provi services to them by government or employer to reduce heat load. This cross–sectional study was conducted in the hottest days of the summer 2015 in Shabestar, Iran and 53 healthy men in nine occupational groups including concrete makers, porters, construction, waste site and road making workers, stonemasons, farmers, traffic officers, and street vendors participated. A set of physiological parameters, like heart rate, blood pressure, skin temperature and etc., WBGT index details and some of the adaptive and protective parameters were measured and monitored simultaneously at different times of the day. The study finds that heat exposure in outdoor workplace is prevalent and WBGT TWA/TLVave is less than 1 in some groups like stonemasons, waste site workers, traffic officers and street vendors whereas in other studied occupations, it is more than 1.This matter is compounded by the fact that the provision of health services by employers or local government was limited, and almost all of the participants had poor or insufficient access levels to public health and welfare services. This study confirms the necessity of interventions by a range of factors, such as government plans, improvement of services in the prevention of heat stress, and planning training courses for outdoor workers to build their knowledge of heat stress

Study On The Acoustic Characteristics Of Natural Date Palm Fibres: Experimental And Theoretical Approaches

The present study deals with the acoustic performance of natural fibres originated from the date palm empty fruit (DPEFB) fibres which is mainly considered as agricultural waste. The fibres were processed and fabricated to be sound absorber samples with two different densities of 100 kg/m3 and 200 kg/m3 and with thicknesses of 10–40 mm. The normal incidence absorption coefficients of the sound absorbers were measured using an impedance tube based on ISO 10534-2. The effects of fibre density and sample thickness are discussed. The findings reveal that for density of 100 kg/m3 the absorption coefficient is 0.6–0.8 above 1.5 kHz for the samples with the thickness of 20 mm and 30 mm. For the thickness of 40 mm, the values even reached the value of 0.9. The values can reach 0.7–0.8 above 1 kHz for the density of 200 kg/m3. Mathematical model using the optimized Delaney-Bazley model with Nelder-Mead simplex method is shown to successfully predict the sound absorption coefficient of the fibre samples. The Johnson-Champoux-Allard model follows the trend of the absorption coefficient, but underestimates the measured data at high frequencies above 2.5 kHz

Wood chip sound absorbers: Measurements and models

Normal incidence absorption coefficient spectra of samples made from glued wood chips have been measured for various mesh sizes, bulk densities, thicknesses, and air gaps. Increasing thickness introduces additional layer resonance peaks and shifts the initial peak towards lower frequencies. The wood chip samples composed of the smallest mesh sizes were found to offer the highest sound absorption, comparable with that of the same thickness of materials made from synthetic fibers. Measured absorption spectra are compared with predictions of four models for the acoustical properties of rigid porous media. These include a model for slanted parallel identical uniform slits (SS), the Johnson-Champoux-Allard (JCA) and Johnson-Champoux-Allard-Lafarge (JCAL) models for arbitrary pore structures, and model for a non-uniform pore size distribution (NUPSD). Porosity and flow resistivity values have been determined non-acoustically. However, the tortuosity and characteristic lengths required for the JCA model have been obtained by fitting the measured absorption spectra. The thermal permeability required for the JCAL model has been deduced indirectly from the fitted tortuosity through a relationship with standard deviation of the pore size distribution due to the NUPSD model. JCAL and JCA models give the best agreement overall, but predictions of the SS and NUPSD models that use only the fitted tortuosity in addition to measured porosity and flow resistivity are found to give comparable agreement with data for many samples. SS and NUPSD predictions are improved by increasing the tortuosity values compared with those obtained by fitting the JCA model. The study should encourage the creation of sustainable sound-absorbing materials from wood chip wastes

Role of Psychosocial Job Stressors on Sexual Function of Male Nurses: The Mediator Role of Work Ability

There is limited information on the specific psychosocial risks at work that can impact sexual function. The general aim of this study was to investigate the effects of multiple dimensions of psychosocial work stressors on the male sexual function. This was a cross-sectional study conducted among 153 male nurses working in two hospitals in Iran. Sexual function and psychosocial job stressors were measured using the Persian version of the International Index of Erectile Function (P-IIEF) and the Persian version of the Health and Safety Executive (P-HSE) Management Standards Indicator Tool. The Persian version of the Work Ability Index (P-WAI) was used to assess the mediating effect of work ability on the relationship between overall stress and subscales of sexual function. The data were analyzed using Pearson product–moment correlation, one-way analysis of variance (ANOVA), and multiple linear regressions. The subscales of psychosocial job stressors, especially the subscale of role, had a significant correlation with several domains of sexual function. The regression modeling indicated that the subscales of role and job demands were significant predictors of various domains of sexual function. The effect of overall stress on intercourse satisfaction was fully mediated by WAI. In the other indicators of sexual function, overall stress score had only a significant direct effect, not mediated by WAI. Intervention programs to improve sexual function should focus on increasing nurses’ involvement in making decisions related to jobs and on using ergonomic principles related to balancing job demands and the level of nurses’ capabilities

Health-related Quality of Life in Two Factories in Yasuj City

Background & aim: Work is an important component of QOL therefore work-related factors could be a significant predictor in this respect.The current study was aimed to asses QOL and its association with socio-demographic, health and work-related factors in two factories in Yasuj, Iran. Methods: In the present cross-sectional study, participants were 280 workers of two factories. The Persian version of World Health Organization Quality of Life-Brief (WHOQOL-BREF) was used to assess the QOL. A questionnaire was developed to assess the socio-demographic, health and work-related factors. Data were analyzed using descriptive statistics. Results: The present study revealed that the means (SD) of physical health, psychological health, social relationships, and environment domains of QOL were 13.2 (2.7), 13.3 (2.6), 14.2 (3.5) and 12.6 (2.5), respectively. A multiple linear regression demonstrated that the types of job, exercise activity, working schedule, sleep quality, smoking, and conflict between work and social life were associated with physical health domain whereas, working schedule, marital status, working demand, sleep quality, BMI, and conflict between work and individual life were significantly associated with psychological health domain. Working schedule, working demand, sleep quality, conflict between work and individual life were significantly associated with social relationship domain however, working demand, working schedule, smoking, sleep quality, working hour, job satisfaction, marital status and exercise activity were significantly associated with environment domain. Conclusion: To improve workers' QOL, the intervention programs should focus on improving work environment, working schedule, occupational training and restricting working hours

Investigating the Effect of Urban Traffic Noise Pollution on University Students\' Cognitive Performance: A Simulated Study

Background and purpose: Cognitive performance in workplace encompasses a wide range of work-related psychological activities. Meanwhile, personality traits as a mediating variable has a determining role in mental functions and occurrence of errors. The aim of this study was to investigate the effect of urban traffic noise pollution on working memory and sustained attention considering personality features in university students. Materials and methods: This interventional laboratory study was performed in 70 students. Urban traffic noise (Sari, north of Iran) was recorded and then the Cool Edit Pro software was used to check, edit the recorded noise, and prepare an audio clip. The students' cognitive performance were assessed using working memory (n-back task) and psychomotor consciousness task (PVT). Results: The mean ages of male and female students were 23.63±3.15 and 24.17±4.23, respectively. According to the Wilcoxon test, a significant relationship was seen between cognitive performances before and after exposure to urban traffic noise (P<0.05). In fact, after exposure to traffic noise, the mean reaction time, response time, and the number of incorrect answers in cognitive tests increased by 8.54%, 9.11%, and 60.61%, respectively. Also, there was an inverse significant correlation between neuroticism and reaction time and accuracy (percentage of correct answers) in students' cognitive performance associated with working memory and sustained attention (P<0.05). Conclusion: Current study can be effective in improving cognitive performance, adopting management strategies in selection of individuals, and establishing a balance between traffic noise and cognitive features in the workplace

Sound Absorption Performance Of Natural Fiber Composite From Chrome Shave And Coffee Silver Skin

This paper presents the sound absorption performance of natural fiber composites developed from chrome shave (CS) and coffee silver skin (CSS). Twelve test samples of thickness 30 mm and 50 mm were fabricated with different fiber sizes and fiber ratios and by maintaining the density of the samples by 150 kg/m3. Normal incidence sound absorption coefficient spectra were measured in an impedance tube. Absorption coefficient spectra were predicted using the Johnson-Allard-Champoux (JCA) model using best fit values of tortuosity and the two characteristic lengths together with measured values of porosity and flow resistivity. The results revealed that the CS-CSS composite had average absorption coefficient of 0.95 above 1 kHz for a thickness of 30 mm and 50 mm. 'The predictions and data are in good agreement up to 6 kHz

Acoustic properties of 3D printed bio-degradable micro-perforated panels made of Corkwood Fiber-Reinforced composites

Introduction: Micro perforated panel (MPP) absorbents promise the next generation of sound absorbers as they have significant advantages over other porous adsorbents. In this study, we will investigate the acoustic performance of MPP absorbents made of biodegradable polylactic acid composite reinforced with natural corkwood fibers (PLA/Corkwood) by 3D printing technology. Material and Methods: First, the effective dimensional characteristics of the parameters were determined, then, all of the samples were fabricated by the Zortrax M200 3D-Printer using the FDM method. The normal incidence sound absorption coefficient of the samples was measured using an acoustic impedance tube according to ISO 10534-2 in the frequency range of 64 to 1600 Hz. Then the effect of four geometric parameters, including hole diameter, panel thickness, perforation ratio, and air gap depth, on the absorption coefficient was studied. Results: The findings show that the SL-MPP 12 absorbent has the highest average sound absorption coefficient (SACA) with a value of 0.28, so that at a frequency of 804 Hz it has the highest sound absorption equal to 0.91. The parametric study found that as the hole diameter increased, the values of peak adsorption and average absorption coefficient were decreased. Increasing the MPP thickness causes the absorption peak to move towards the lower frequency range. Decreasing the perforation ratio increases the peak absorption values and the average sound absorption, and the frequency with the highest absorption also moves towards the higher frequency range. The resonant frequency also depends on the depth of the air gap behind the screen. Changes in air gap depth from 30 mm to 70 mm reduced the resonant frequency by more than 35%. Conclusion: Using 3D printing technology, sustainable MPP can be fabricated with more quality and in less time than traditional methods such as mixing and heat pressing